A study by Salford University found cars to be 50% dirtier than both of these items.

Researchers collected swabs from around the handbrake, as well as other areas inside cars. These swabs were found to carry a higher density of bacteria than a smartphone screen, or even a computer keyboard – both known to be a hotbed of germs.

Despite this, many drivers believe that their car is one of the cleanest things they own.

However, an online survey conducted by Sellcar.co.uk found that of 2,000 people questioned, 80% only cleaned the inside of their cars once a month or less.

Dr Lisa Ackerly, ‘The Hygiene Doctor’, commented on the findings, saying: “When you think of all the unhygienic things you see people doing while driving – picking their noses, coughing over the steering wheel and eating food – we really ought to be cleaning the insides of our cars more, particularly the hand contact surfaces.”

A lack of care for the interior of a car can also drastically affect its value.

Mark Rogers, managing director of SellCar.co.uk, said: “Cars that are not taken care of will depreciate at a record rate in comparison to those that are regularly maintained.

“It may start with a few germs and not clearing out the rubbish, but this can easily lead to odour lingering in the car that cannot be dispelled or rust accumulating on edges that will put off any prospective buyer and ultimately cause the car to devalue.”

But at least yours won’t get towed away if it’s dirty. Officials in Abu Dhabi have started issuing large fines and confiscating cars under laws introduced to protect the city’s appearance.

Many in the UAE capital leave their cars parked in residential zones – with valid permits – while they travel abroad over summer.

But while they’re away, their cars get covered in dirt and dust – leading to officials confiscating them for “disfiguring the public appearance”.